| Aircraft Steels |
19-Feb-2009 |
46 pages |
| Authors:
R Taylor; E U Lee; C Lei; H C Sander; NAVAL AIR WARFARE CENTER AIRCRAFT DIV PATUXENT RIVER MD
|
 | Five high strength steels (4340, 300M, AerMet 100, Ferrium S53, and Hy-Tuf) and four stainless steels (High Nitrogen, 13-8Mo, Custom 465, and MLX17) have been evaluated with respect to their characteristics and applicability to the current and future Navy aircraft. In this endeavor, their metallurgical feature, mechanical property, fatigue behavior, and corrosion resistance have been investigated and compared. |
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| Evaluation of the StressWave Cold Working (SWCW) Process on High-Strength Aluminum Alloys for Aerospace |
Feb-2009 |
61 pages |
| Authors:
Eric T Easterbrook; Michael A Landy; STRESSWAVE INC KENT WA
|
| This report was developed under a SBIR contract. A new and innovative cold working process called StressWave Cold Working (SWCW) was investigated and compared to the conventional split sleeve cold working method that is used to enhance the fatigue life of fastener holes in high strength aluminum alloys used on USAF aircraft structures. StressWave cold working was found to be superior in enhancing fatigue lives compared to split sleeve cold ... |
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| Atomic Scale Structure and Chemical Composition Across Order-Disorder Interfaces (POSTPRINT) |
Jul-2008 |
6 pages |
| Authors:
J Tiley; J Y Hwang; R Banerjee; R Srinivasan; G B Viswanathan; H L Fraser; D M Dimiduk; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
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| The high strength of many metallic alloys, especially at elevated temperatures, including nickel base superalloys used in aircraft jet engines, is often attributed to the presence of homogeneously distributed second phase precipitates within a disordered matrix. In superalloys, the ordered precipitate/disordered matrix interface plays a critical role in determining the precipitate coarsening kinetics as well as the strengthening mechanism at high temperatures. Combining aberration-corrected high resolution scanning transmission electron microscopy ... |
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| Microstructural Evolution during the Dynamic Deformation of High Strength Navy Steels |
19 MAY 2008 |
36 pages |
| Authors:
K. S. Kumar; BROWN UNIV PROVIDENCE RI DIV OF ENGINEERING
|
| We have characterized the propensity for adiabatic shear band formation (an associated microstructural evolution) under dynamic deformation conditions in an ultra-high strength (160 Ksi/I 1.1GPa) Fe-10 Ni-0.lC-Cr,Mo,V steel and demonstrated that this steel is highly prone to shear localization and failure. In the as-received condition, the steel has a lath martensite microstructure. During dynamic deformation, shear localization occurs and manifests by an optically visible shear band; the original microstructure is ... |
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| Improved Navy Maintenance Through Corrosion-Fatigue Assessment Program |
11-Mar-2008 |
237 pages |
| Authors:
Wally Hoppe; DAYTON UNIV RESEARCH INST (URDI) OH STRUCTURAL INTEGRITY DIV
|
| The High-Strength Steel Corrosion-Fatigue Assessment program was designed to ensure reliability and supportability of current and emerging Naval aircraft by providing requisite engineering support to evaluate issues relevant to corrosion-fatigue of aircraft components. In this multi-year, multi-contract program, tools have been developed to assist in the establishment of maintenance options for corroded components. Experimental and analytical tools have been developed to classify corrosion in a manner tied to a reduction ... |
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| Lightweight Multifunctional Linear Cellular Alloy Ballistic Structures |
26 APR 2006 |
16 pages |
| Authors:
Joe K. Cochran; STRUCTURED ALLOYS INC MARIETTA GA
|
| The objective of this effort was to develop the techniques for fabricating a multifunctional lightweight structure that could be used as armor for mobile vehicles such as personnel carriers. These fabrication techniques are scalable to manufacturing production levels. For this program, square cell LCA honeycomb with both maraging steel and super invar compositions were fabricated using SAI's patented technology to have cross sections of one inch square. These honeycombs have ... |
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| Hydrogen Environment Assisted Cracking of Ultra-High Strength AetMet(Trademark) 100 Steel |
2006 |
42 pages |
| Authors:
Yongwon Lee; Richard P. Gangloff; VIRGINIA UNIV CHARLOTTESVILLE DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| Precipitation hardened martensitic AetMet(tradeMark) 100 is a high purity ultra-high strength steel with exceptional plain strain fractare toughness (K(sub IC) 130 MPa square root to m) and high yield strength (sigma YS 1725 MPa). The hydrogen envfronment assisted cracking (FlEAC) behavior of this modem steel is not w#1 understood, and was characterized in neutral 3.5% NaCl solution at various applied potentials (E(sub App)) relevant to coated applications in marine environments. ... |
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| Electrochemical Mitigation of hydrogen Environment Embrittlement of Ultra-High Strength AerMet(Trademark) 100 |
2006 |
29 pages |
| Authors:
Samil Al-Ghamdi; John R. Scully; VIRGINIA UNIV CHARLOTTESVILLE OFFICE OF SPONSORED PROGRAMS
|
| The goal of this research is to extend the potential region of high toughness in an ultra-high strength steel (UHSS) to anodic and cathodic potentials where hydrogen environment embrittlement (HEE) is normally observed due to hydrogen uptake in the absence of inhibitors. This is being explored through the investigation of several selected chemical inhibitors (anodic inhibitors and cathodic blocking agents). The research is conducted in three stages. The effect of ... |
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| High Strength Steel Welding Research |
27 MAY 2005 |
470 pages |
| Authors:
Stephen Liu; Glen Edwards; COLORADO SCHOOL OF MINES GOLDEN CENTERFOR WELDING JOINING AND COATINGS RESEARCH
|
| The application of high strength low alloy (HSLA) steels has been limited by the availability of suitable filler metals. Specifically, as the weld metal strength increases, the susceptibility to hydrogen-assisted cracking increases. To take full advantage of the developments in HSLA steel base metals, weld filler metals which minimize the effects of diffusible hydrogen and develop tough microstructures must be designed. The benefit of yttrium-containing inclusions to provide effective hydrogen ... |
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| iMAST Quarterly, Number 2, 2005 |
Jan-2005 |
9 pages |
| Authors:
Timothy J Eden; PENNSYLVANIA STATE UNIV UNIVERSITY PARK APPLIED RESEARCH LAB INST FOR MANUFACTURING AND SUSTAINMENT TECHNOLOGIES
|
| World events have emphasized the importance of developing light weight, high-performance materials, especially those that can be used in armor and blast resistance structures. Recent work at Penn State's Applied Research Laboratory has produced some high performance aluminum alloys. These materials, produced by Spray Metal Forming, have superior properties which have shown potential for use in military vehicles to provide light-weight ballistic protection. |
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| Investigation of Structure, Properties and Deformation Mechanisms of Elevated Temperature Al Alloys with High Specific Properties |
31 JAN 2004 |
113 pages |
| Authors:
Yuly V. Milman; UKRAINIAN ACADEMY OF SCIENCES KIEV INST OF MATERIALS SCIENCE PROBLEMS
|
| The present project was devoted to the investigation of structure and mechanical properties of high-strength aluminum alloys especially alloys for elevated temperatures. High-strength aluminum alloys can have strengths approximately 50 times higher than the strength of unalloyed aluminum. Such a strong increase of the alloy strength is a unique case in the science of metallic materials and is a consequence of a tremendous number of theoretical and experimental works. For ... |
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| Hydrogen Assisted Cracking of High Strength Alloys |
AUG 2003 |
195 pages |
| Authors:
Richard P. Gangloff; ALUMINUM CO OF AMERICA ALCOA CENTER PA ALCOA TECHNICAL CENTER
|
| Two important advances over the past 40 years enable the optimization and management of the structural integrity of components in high performance applications. First, the solid mechanics conununity established linear elastic fracture mechanics as the premier framework for modeling the damage tolerance of fracture critical components (Irwin and Wells, 1997; Paris, 1998). Second, materials scientists developed metals with outstanding balances of high tensile strength and high fracture toughness (Garrison, 1990; ... |
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| Mechanisms of Crack Tip Hydrogen Embrittlement in High Strength Alloy Steels for Marine Applications |
OCT 2002 |
220 pages |
| Authors:
R. P. Gangloff; J. R. Scully; E. Richey III; R. L. Thomas; D. Li; VIRGINIA UNIV CHARLOTTESVILLE OFFICE OF SPONSORED PROGRAMS
|
| The primary objective of this research was to characterize and understand (a) the interaction of a range of bulk-dissolved hydrogen concentrations with the complex tempered martensitic microstructure of AerMet 100 ultra-high strength steel, (b) the effect of such trapped hydrogen on fracture resistance associated with internal hydrogen embrittlement (IHE), and (c) the levels of trapped and diffusible hydrogen achieved after cadmium plating and baking operations. Studies of hydrogen transport rates, ... |
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| Restoring Fatigue Performance of Corrosion Damaged Aa7075-T6 and Fretting in 4340 Steel with Low Plasticity Burnishing |
SEP 2002 |
8 pages |
| Authors:
Paul S. Prevey; John T. Cammett; LAMBDA RESEARCH CINCINNATI OH
|
| Corrosion related fatigue in aluminum structural alloys and fretting damage in high strength steels are primary failure mechanisms that reduce the structural integrity of aging aircraft. A chemically active environment, susceptible material and static and/or alternating tensile stresses are all required for failure. Conventional approaches to mitigate corrosion and fretting related failure mechanisms address either elimination of the corrosive environment with coatings, substitution or modification of alloys, or changes in ... |
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| High-Temperature Fatigue Cracking Mechanisms |
31 AUG 2001 |
100 pages |
| Authors:
Keh-Minn Chang; Bernard Cooper; Bruce Kang; WEST VIRGINIA UNIV MORGANTOWN
|
| The objective of this research is to develop a comprehensive understanding of high-temperature fatigue cracking mechanisms in various high- strength superalloys. The alloying effects on fatigue cracking resistance will be studied through a multi-disciplinary effort, which combines metallurgy, micro-mechanics, finite element analysis, and material physics. |
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| High Strength Steel Weldment Reliability |
AUG 2001 |
46 pages |
| Authors:
D. L. Olson; COLORADO SCHOOL OF MINES GOLDEN CENTERFOR WELDING JOINING AND COATINGS RESEARCH
|
| The development of methods to control the diffusible hydrogen content during high strength steel welding was performed. The perfection of the use of irreversible weld metal hydrogen traps was demonstrated. Efforts have effectively alleviated the available diffusible hydrogen, and thus the susceptibility of hydrogen assisted cracking, by the use of ferro yttrium additions to the welding consumable. The range of welding parameter for the most effective use of yttrium as ... |
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| Advances in Hydrogen Management for High Strength Steel |
07 JUN 2001 |
18 pages |
| Authors:
Yeong-Do Park; Chad Lensing; Iman Maroef; David L. Olson; Zamir Gavra; COLORADO SCHOOL OF MINES GOLDEN CENTERFOR WELDING JOINING AND COATINGS RESEARCH
|
| Diffusible hydrogen content in high strength low alloy steels welding can be better managed with modifications to the low hydrogen welding consumables. The welding consumable alloy content needs to allow the weld metal to transform from austenite to ferrite/martensite at slightly higher temperature than the base metal does. This practice will allow for the best dispersal of hydrogen from the weld deposit and minimizing the tendency of localizing the hydrogen ... |
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| Continuous Dynamic Recrystallization During Friction Stir Welding of High Strength Aluminum Alloys |
SEP 2000 |
|
| Authors:
K. V. Jata; S. L. Semiatin; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
 | Friction stir welding (FSW) is a solid state joining process 1,2,3 that uses a rapidly-rotating, non-consumable high strength tool-steel pin that extends from a cylindrical shoulder (Figure 1). The workpieces to be joined are firmly clamped to a worktable; the rotating pin is forced with a pre-determined load into them and moved along the desired bond line. Frictional heating is produced from the rubbing of the rotating shoulder with the ... |
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| Dynamic Constitutive and Failure Characterization of Rate Sensitive Alloys |
20 JUN 2000 |
8 pages |
| Authors:
Ares J. Rosakis; G. Ravichandran; CALIFORNIA INST OF TECH PASADENA OFFICE OF SPONSORED RESEARCH
|
| The objectives of this research program are (1) to establish critical conditions for initiation and growth of adiabatic shear bands in pre-notched plates subjected to asymmetric impact loading and (2) investigate the transition between competing failure modes under varying loading conditions. Typically, failure under asymmetric loading may occur by either dynamic cracking or adiabatic shear banding, both of which may be observed in the same specimen or ... |
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| Fundamental Investigations of Plasticity in High Strength Nanostructured Aluminum Alloys |
2000 |
8 pages |
| Authors:
Rajiv S. Mishra; MISSOURI UNIV-ROLLA DEPT OF METALLURGICAL ENGINEERING
|
| Cryomilled aluminum alloys are being developed for aerospace applications. These high-strength aluminum alloys are currently targeted for low-temperature rocket applications. This research focused on the fundamental strengthening mechanisms in these alloys. The primary sources of strengthening in cryomilled aluminum alloys are dispersion of nanocrystalline particles and ultrafine grain size that form during the cryomilling stage. Optimized thermo- mechanical processing of cryomilled powder results in an ultrafine grain size material with ... |
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| Titanium Carbosulfides and the Fracture Toughness of Ultra High StrengthSteels |
NOV 1999 |
64 pages |
| Authors:
Warren M. Garrison Jr.; CARNEGIE-MELLON UNIV PITTSBURGH PA
|
| The objectives of this work were to calculate from first principles the work of adhesion associated with the steel-MnS and steel-Ti2CS interfaces and to examine with transmission electron microscopy void nucleation at particles of MnS and particles of Ti2CS in steel. The motivation for this work was the observation that gettering sulfur as Ti2CS rather than as MnS leads to doubling and even tripling of ... |
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| Development of Compliance Expression for Deeply Flawed 1T-WOL Specimen |
AUG 1999 |
14 pages |
| Authors:
P. W. Holsberg; R. A. Hayes; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD
|
| It is difficult to make precise load measurements in 1T-WOL specimens where significant crack extension (the ratio of the final crack length to specimen width exceeds 0.8) has occurred during testing An alternate method to determine this load would be from compliance calculation using the original, measured crack mouth opening displacement. Such an equation has been derived and verified. |
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| The Effects of Retained Austenite on the Tensile Properties and Toughness of Ultra-High Strength Martensitic Precipitation Hardened Stainless Steels |
14 DEC 1998 |
47 pages |
| Authors:
Warren M. Garrison; CARNEGIE-MELLON UNIV PITTSBURGH PA DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| The purpose of this work was to assess the effects of the amount of retained austenite content on the ductile-to-brittle transition temperature of martensitic precipitation strengthened stainless steels for four different precipitation strengthening systems, one utilizing NiTi strengthening and three utilizing R-phase strengthening. The retained austenite contents in the four systems were varied by varying composition. The austenite content in the NiTi strengthened system was varied by varying the chromium ... |
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| The Role of Vanadium Carbide Traps in Reducing the Hydrogen Embrittlement Susceptibility of High Strength Alloy Steels |
AUG 1998 |
27 pages |
| Authors:
G. L. Spencer; D. J. Duquette; ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER WATERVLIET NY BENET LABS
|
| High strength alloy steels typically used for gun steel were investigated to determine their susceptibility to hydrogen embrittlement. Although AISI grade 4340 was quite susceptible to hydrogen embrittlement, ASTM A723 steel, which has identical mechanical properties but slightly different chemistries, was not susceptible to hydrogen embrittlement when exposed to the same conditions. The degree of embrittlement was determined by conducting notched tensile testing on ... |
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| High Strength Steel Welding Research |
AUG 1998 |
233 pages |
| Authors:
Glen R. Edwards; David L. Olson; Stephen Liu; COLORADO SCHOOL OF MINES GOLDEN CENTERFOR WELDING RESEARCH
|
| By optimizing the contents of microalloying elements and elements that promote dual precipitation, a family of welding consumables with excellent characteristics were developed. These electrodes were insensitive to moderate variations in chemical composition or cooling rate, had acceptable strength and impact toughness, and exhibited more uniform mechanical properties throughout the entire weldment cross-section, including the reheated weld zones. An electrode containing 1.25 wt. pct. ... |
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| High Strength Steel Weldment Reliability: Weld Metal Hydrogen Trapping |
FEB 1998 |
265 pages |
| Authors:
David L. Olson; COLORADO SCHOOL OF MINES GOLDEN CENTERFOR WELDING JOINING AND COATINGS RESEARCH
|
| The potential use of weld metal hydrogen getters (traps) to increase the reliability of high strength steel weldments was investigated. This research aimed to establish a fundamental understanding of the trapping mechanisms in weld metal and to evaluate the effectiveness of irreversible traps introduced by specific alloying additions, in comparison to the reversible hydrogen trapping by weld metal constituents and solidification substructure. The work involved: (1) fundamental calculations to select ... |
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| Stress Concentrators and Rate Effects in Formation of Adiabatic Shear Bands |
JAN 1998 |
42 pages |
| Authors:
Janusz R. Klepaczko; METZ UNIV (FRANCE) LAB OF PHYSICS AND MECHANICS OF MATERIALS
|
| This Final Technical Report covers the contract period from 7 Nov 96 to 6 Jan 98. A more detailed information on the progress of this Contract can be found in the previous Interim Reports. During the period under consideration the research has been continued on analyses of experimental results obtained via the Modified Double Shear experimental technique (MDS). This technique has been applied for VAR 4340 steel with the heat ... |
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| Numerical Study of Stress Concentrators in Impact Shearing |
1998 |
28 pages |
| Authors:
M. Klosak; J. R. Klepaczko; METZ UNIV (FRANCE) LAB OF PHYSICS AND MECHANICS OF MATERIALS
|
| This Appendix contains complete results of numerical calculations by FE code ABAQUS/Explicit for four geometries of a shear layer with different stress concentrators. All calculations have been performed for VAR 4340 steel with hardness 50 HRC. Several shear velocities have been assumed, from 10 m/s to 150 m/s. Because of thermal coupling the local heating around a stress concentrator leads to failure due to carrying capacity of the material. Two ... |
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| Characterization of Hydrogen Ingress in High-Strength Alloys |
NOV 97 |
93 pages |
| Authors:
Bruce G. Pound; SRI INTERNATIONAL MENLO PARK CA
|
| The effect of heat treatment on irreversible hydrogen trapping was investigated for high strength steels (4340, 18Ni (250), and AerMet 100), alloy K-500, and precipitation-hardened alloys (X-750 and 18Ni (250) steel), with the goal of providing insight into the factors governing the intrinsic susceptibility to hydrogen embrittlement (HE). A potentiostatic pulse technique was used to determine irreversible trapping constants (k), which were compared with changes in strength and microstructure. Irreversible ... |
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| Hydrogen Cracking During Service of High Strength Steel Cannon Components |
SEP 97 |
27 pages |
| Authors:
J. H. Underwood; E. Troiano; G. N. Vigilante; A. A. Kapusta; S. Tauscher; ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER WATERVLIET NY BENET WEAPONS LAB
|
| An investigation of environmental cracking during service of high strength steel cannon components is described. Two cases of cracking occurred in similar prototypes of an advanced cannon over a two-year period. The materials, components configurations, applied and residual stresses, environmental conditions, and the resulting cracking behaviors and SEM fracture surface characteristics are outlined. Laboratory hydrogen cracking tests of the cannon materials, finite element stress analysis, and stress intensity factor calculations ... |
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| Hydrogen-Induced Cracking Tests of High-Strength Steels and Nickel-Iron Base Alloys Using the Bolt-Loaded Specimen |
MAR 97 |
27 pages |
| Authors:
G. N. Vigilante; J. H. Underwood; D. Crayon; S. Tauscher; T. Sage; ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER WATERVLIET NY BENET LABS
|
| Hydrogen-induced cracking tests were conducted on high strength steels and nickel-iron base alloys using the constant displacement bolt-loaded compact specimen. The bolt-loaded specimen was subjected to both acid and electrochemical cell environments to produce hydrogen. The materials tested were A723. Maraging 200, PH 13-8 Mo. Alloy 718, Alloy 706, and A286, ranging in yield strength from 760-1400 MPa. The effects of chemical composition, refinement, heat treatment, and strength on hydrogen-induced ... |
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| Mechanisms for the Hydrogen Environment Embrittlement Resistance of High Strength Alloys |
JAN 97 |
253 pages |
| Authors:
R. P. Gangloff; J. R. Scully; R. G. Kelly; VIRGINIA UNIV CHARLOTTESVILLE DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| The objectives of this research are to: (1) identify conditions under which high strength beta titanium alloys and Fe-Ni-based superalloys resist environment assisted cracking (EAC) in marine environments; (2) characterize EAC initiation and propagation versus metallurgical, chemical, and mechanical variables that may destabilize the crack tip passive film to promote both dissolution and hydrogen uptake; (3) test the hydrogen embrittlement mechanism; and (4) model EAC by integrating crack chemistry, surface ... |
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| Characterization of Hydrogen Ingress in High-Strength Alloys |
JAN 97 |
18 pages |
| Authors:
B. G. Pound; SRI INTERNATIONAL MENLO PARK CA
|
| The effect of heat treatment on irreversible hydrogen (H) trapping was investigated for Alloy K-500 UNS N05500, with the goal of providing a more detailed insight into the factors governing the intrinsic susceptibility to hydrogen embrittlement (HE). A potentiostatic pulse technique was used to determine irreversible trapping constants (k) and H entry fluxes for annealed and annealed-aged (AA) specimens of old drawn Alloy K-500 that had been used earlier to ... |
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| Characterization of Hydrogen Ingress in High-Strength Alloys |
NOV 95 |
107 pages |
| Authors:
Bruce G. Pound; SRI INTERNATIONAL MENLO PARK CA
|
| The ingress of hydrogen (H) in various high-strength alloys was investigated with a view to characterizing their susceptibility to hydrogen embrittlement (HE). A potentiostatic pulse technique was applied to three Fe- base alloys (AerMet 100, H11, and A-286), two Cu-containing alloys (Be-Cu and alloy K-500), a superferritic stainless steel (Sea-Cure), and three Beta-Ti alloys (Ti-15V-3Cr-3Al-3Sn, Beta-21S, and Beta-C) in 1 mol/L acetic acid-1 mol/L sodium acetate. The data were analyzed ... |
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| Contact Corrosion Between Carbon Fiber Reinforced Composite Materials and High-Strength Metals |
09 AUG 95 |
15 pages |
| Authors:
Mantong Gao; Changgan Xu; Zeyi Du; Tiemin Wang; NATIONAL AIR INTELLIGENCE CENTER WRIGHT-PATTERSON AFB OH
|
| Experimental results show that when carbon fiber/epoxy resin composite materials are joined with high-strength titanium alloys, aluminum alloys, lCrl8Ni9Ti stainless steel, or other structural materials, galvanic corrosion and crevice corrosion take place on the contact boundaries. This corrosion is primarily determined by the electrochemical properties of the materials. It is also related to the materials' mutual coupling situation, treatment technology, and environmental conditions. Galvanic corrosion is affected by the coupled ... |
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| Development of High Performance Steels for Bridge Construction |
AUG 95 |
37 pages |
| Authors:
Eric M. Focht; Thomas W. Montemarano; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD
|
| High strength steels that are used in bridge construction (ASTM A709) have yield strengths in the 50 to 100 ksi range and allow for carbon levels to reach as high as 0.23 wt.%. For good weldability, the carbon content in HSLA steels used by the Navy is usually restricted to a maximum of 0.10 wt.%. The Navy is working with industry to develop new high performance steels for bridges with ... |
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| Low Cycle Notched Fatigue Behavior and Life Predictions of A723 High Strength Steels |
APR 95 |
26 pages |
| Authors:
E. Troiano; J. H. Underwood; D. Crayon; R. T. Abbott; ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER WATERVLIET NY BENET LABS
|
| Two types of ASTM A723 steels have been investigated for their low cycle fatigue behavior (less than 104 cycles to failure). Specimens were tested in four-point bending, both with and without notches, and the measured fatigue lives were compared with those predicted by Neuber notch analysis (classic and elastic/plastic remote applied loading), and standard fracture mechanics life prediction techniques. Comparison of measured and predicted lives indicates that the elastic/plastic Neuber ... |
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| Effect of Impurities on the Electronic Structure of Grain Boundaries and Intergranular Cohesion in Tungsten |
FEB 95 |
16 pages |
| Authors:
Genrich L. Krasko; ARMY RESEARCH LAB WATERTOWN MA MATERIALS DIRECTORATE
|
| The cohesion of a grain boundary (GB) is believed to be the controlling factor limiting the ductility of high-strength metallic alloys. and particularly those containing W. Intergranular embrittlement is usually associated with segregation of impurities at the GBs. Impurities present in ppm concentrations can result in a dramatic decrease in plasticity. This paper reviews recent results on both semi-empirical and first-principles modelling of the energetics and the electronic structures of ... |
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| Correlation of Inclusion Size and Chemistry with Weld Metal Composition and Microstructure Arc Weldments of High Strength Steels |
DEC 94 |
144 pages |
| Authors:
Mark W. Eakes; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Non-metallic inclusions are crucial to the development of acicular ferrite, the desired microstructure for optimal strength and toughness in weld metal. This study focused on obtaining correlation between the size and chemistry of inclusions and weld metal properties, especially the amount of acicular ferrite, in Gas Metal Arc (GMA) and Submerged Arc (SA) weldments in HY- 100 and HSLA-100 steel. A strong correlation was found between the amount of acicular ... |
|
| Environmentally Assisted Cracking of High Strength Beta Titanium Alloys |
NOV 94 |
264 pages |
| Authors:
R. P. Ganglogg; J. R. Scully; R. G. Kelly; VIRGINIA UNIV CHARLOTTESVILLE SCHOOL OF ENGINEERING AND APPLIED SCIENCE
|
| The objective of this integrated research program is to define the conditions under which high strength Beta-titanium alloys resist environmentally assisted cracking (EAC) in marine environments. Specific goals are to: (1) characterize EAC for metallurgical. chemical and mechanical conditions that could - destabilize crack tip passive films to promote local dissolution and hydrogen uptake, (2) test the hydrogen embrittlement mechanism for EAC, and (3) develop a mechanism-based model of EAC ... |
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| Evaluation of a Diffusion/Trapping Model for Hydrogen Ingress in High- Strength Alloys. |
NOV 1994 |
69 pages |
| Authors:
Bruce G. Pound; SRI INTERNATIONAL MENLO PARK CA
|
| The ingress of hydrogen in various high-strength alloys was investigated with a view to characterizing their susceptibility to hydrogen embrittlement (HE). A potentiostatic pulse technique was applied to two precipitation-hardened iron-base alloys (AerMet 100 and alloy A-286), two Cu- containing alloys (Be-Cu and alloy K-500), and a superferritic stainless steel (UNS 544660) in 1 mol/L acetic acid-1 mol/L sodium acetate. The data were analyzed using a diffusion/trapping model to obtain ... |
|
| Evaluation of Prototype Secondary Hardening Steels for Armor |
NOV 94 |
21 pages |
| Authors:
John H. Graves; John H. Beatty; Morris Azrin; ARMY RESEARCH LAB WATERTOWN MA MATERIALS DIRECTORATE
|
| Three ARL .SRG secondary hardening armor steels designed using the THERMOCALC thermomechanical database and software system were subjected to ballistic impact using U.S. .30 caliber AP M2 and U.S. .50 caliber AP M2 projectiles. Against the .30 caliber projectile, each of the three steel alloys showed ballistic tolerance comparable to AerMet 100 Steel. Against the .50 caliber projectile, the ballistic test plates did not perform as well as AerMet 100. ... |
|
| Bibliography on Hot Isostatic Pressing (HIP) Technology Supplement 1 |
NOV 94 |
|
| Authors:
A. M. Thompson; E. S. Helton; B. F. Gilp; METALS INFORMATION ANALYSIS CENTER WEST LAFAYETTE IN
|
| This report is the first supplement to MIAC Report 1, Bibliography on Hot Isostatic Pressing (HIp) Technology and contains an annotated bibliography of the Hot Isostatic Pressing (HIP) Technology dealing with metals, alloys, and intermetallic compounds. Bibliographic information is organized according to major alloy groups, e.g., aluminum alloys, beryllium alloys, cobalt alloys, etc. , following by bibliographies for miscellaneous alloys which are alloys either not properly identified or not having ... |
|
| The Resistance of High-Strength Alloys to Hydrogen Embrittlement |
JUN 94 |
14 pages |
| Authors:
Bruce G. Pound; SRI INTERNATIONAL MENLO PARK CA MATERIALS RESEARCH CENTER
|
| The resistance of an alloy to hydrogen embrittlement (HE) is strongly influenced by the presence of microstructural heterogeneities, which can provide sites to trap hydrogen. The entry and trapping of hydrogen in a range of high- strength alloys have been investigated with a technique referred to as hydrogen ingress analysis by potentiostatic Pulsing (HIAPP). Data were analyzed by using a diffusion/trapping model to determine entry and trapping parameters for high- ... |
|
| The National Shipbuilding Research Program. 1993 Ship Production Symposium. Paper No. 25: Measured Imperfections and Their Effects on Strength of Component Plates of a Prototype Hull Structure |
NOV 1993 |
15 pages |
| Authors:
Alan A. Pang; Robert Tibert; Le W. Lu; James Ricles; Robert Dexter; LEHIGH UNIV BETHLEHEM PA
|
| The U.S. Navy is currently studying the use of double hull designs in high strength low alloy (HSLA) steels for surface combatant ships. A full scale prototype double hull module was fabricated, from which multicellular box column specimens were cut for compressive tests to failure. Initial imperfections i.e. initial plate deflections and welding residual stresses, affect the stiffness and strength of welded members. This paper describes the measurement of these ... |
|
| Evaluation of a Diffusion/Trapping Model for Hydrogen Ingress in High- Strength Alloys |
21 NOV 91 |
8 pages |
| Authors:
Bruce G. Pound; SRI INTERNATIONAL MENLO PARK CA
|
| A potentiostatic pulse technique was used to study the ingress of hydrogen in titanium (pure and grade 2) in an acetate buffer. Hydrogen ingress did not occur with pure titanium, indicating that the surface oxide is an effective barrier to hydrogen entry. In contrast, the data for Ti grade 2 were shown to fit a model for hydrogen diffusion and trapping, allowing values to be determined for the irreversible trapping ... |
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| Unusually High Fracture Toughness of ASTM A723 Steel from a Mixed Martensite/Bainite Microstructure |
NOV 90 |
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| Authors:
J. A. Kapp; J. Barranco; L. Meisel; P. J. Cote; R. N. Wright; ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER WATERVLIET NY BENET LABS
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| A mixed martensite/bainite microstructure in the high strength-low alloy steel (ASTM A723 pressure vessel steel) can be obtained by quenching from the austenitizing temperature to below M sub s, but above M sub f, and isothermally holding. As the supercooled austenite cools below M sub s, some martensite is formed and the isothermal hold results in the remainder of the untransformed austenite transforming to bainite. The resulting microstructure may be ... |
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| Microstructural Features Controlling Ductile-to-Brittle Transition Behavior in High-Strength, Martensitic Steel Weld Metals |
OCT 90 |
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| Authors:
J. J. DeLoach Jr; DAVID TAYLOR RESEARCH CENTER BETHESDA MD SHIP MATERIALS ENGINEERING DEPT
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| An investigation of the transition behavior of high strength steel, martensitic weld metals was conducted. The objective of the investigation was to identify the specific microstructural features that control ductile-brittle transition in these weld metals. The approach systematically combined experimental measurements and observations with the use of analytical expressions. Charpy V-notch (CVN) properties, tensile properties, and cleavage fracture stress (sigma c) were generated over a range of temperatures. The critical ... |
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| An Investigation of the Role of Second Phase Particles in the Design of Ultra High Strength Steels of Improved Toughness |
20 JUN 90 |
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| Authors:
W. M. Garrison Jr; CARNEGIE MELLON UNIV PITTSBURGH PA DEPT OF METALLURGICAL ENGINEERING AND MATE RIALS SCIENCE
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| In this report summarized work carried out as part of a research program designed to improve the upper shelf fracture toughness of ultra high strength steels and to gain further understanding of the processes associated with the fracture of these materials and how these processes are related to microstructure. The results emphasized are: (a) blunting behavior and its effects on toughness, (b) the effects of inclusion spacing at constant inclusion ... |
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| Statistical Treatment of Slow Strain Rate Data for Assessment of Hydrogen Embrittlement in Low Alloy High Strength Steel |
APR 90 |
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| Authors:
W. J. Pollock; AERONAUTICAL RESEARCH LABS MELBOURNE (AUSTRALIA)
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| Slow strain rate testing has been used to quantify the degree of hydrogen embrittlement produced in high strength 4340 steel by plating processes and aircraft maintenance chemicals. The results of slow strain rate tests, conducted at a crosshead displacement rate of 2 x 0.0001 mm/s using samples of three notched tension specimens in various paint strippers, show that a mean fracture stress of 1850 MPa can be correlated with the ... |
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Reports by Keyword(s)
*HIGH STRENGTH ALLOYS
